I always used the matchbook cover from a plain old pack of matches. Open it up and use the inside of the matchbook cover. Moisten the sides of the tip and go at it. I liked firm paper (matchbook cover or ?). Dollar bill fair, soft leather ok, business card or 3x5 index card, not bad, matchbook cover Check! Try it, you'll like it. Oh, one more. The paper side of a piece of sandpaper was good also.
Always had that plus a tip tapper (or similar small tool) and a piece of scotchbrite. All small stuff I could carry in my pocket and use so no one noticed. Came in very handy when playing in bars using a house cue. I could make any straight cue play good! For some reason I liked to play with a light cue (15 or 16 oz.) in a bar. Never knew exactly why that worked for me.